Tuesday, October 20, 2009

When first publicly disclosing the outcome of the Thai trial in September, researchers said the vaccine had lowered the risk of infection by about 31%. That result was modest but statistically significant, meaning it wasn't the result of a fluke. That announcement, coming after two decades of failed HIV vaccine trials, garnered headlines around the world.

Now, two other analyses of the trial data suggests that the results could have been due to pure chance, and therefore the vaccine may not have conferred protection to people after all. The additional data are published today in the New England Journal of Medicine and will be more fully discussed today by researchers attending an AIDS meeting in Paris.